How do you mark the anniversary of an event the consequences of which have been a dominant element, not just in the Guardian, but in the news media of the world for the past 12 months? As the editor of the Comment pages put it, "In a way, what have we been writing about for the past year if not the effects of September 11? We wouldn't now be talking about war in Iraq were it not for September 11."

You could not not mark the anniversary - the appetite reflects the anxiety. But no one involved in the past couple of months in planning the Guardian coverage wanted to rerun the events of the actual day, particularly visually, although a great deal of that material will be on the Guardian's website. I wrote at the time, explaining how the paper of September 12 was produced - how it ran through its first three pages with hardly a word - a speechlessness that seemed appropriate. The front page was a picture of the twin towers at the moment of the second impact, and across pages two and three, a single photograph of the pall hanging over the New York skyline. It was the briefest silence.

In the news pages in the past week the anniversary has been used in part as a moment to pause and take stock. Some of this - perhaps 12,000 words produced by deploying at least nine Guardian journalists in 11 countries - has attempted to analyse the current state and capability of al-Qaida and to assess the progress and prospects of the "war on terrorism".

The deputy editor of the paper said: "We did not want our coverage to be just about looking back. We didn't want it to be just about the US. We've tried to treat September 11 like a stone in a pond with ripples that have reached everywhere, using journalism to tell you something you didn't know." The coverage this week will include a survey of effects on economies round the world and an audit of legislation that has followed the event, threatening to restrict civil and political liberties.

One of the editors involved in coordinating the foreign coverage said the striking thing for her was that the actual events of September 11 seemed so recent, certainly not like a year ago.

Several other journalists made a similar point, that time had somehow been collapsed. The events and images of the day are seared into our minds. Perhaps that was what one of the paper's cartoonists (Peter Till) was thinking of when he illustrated a piece on the Comment pages with a face, the nose formed by the twin towers, the mouth the ground, the eyes by the converging aircraft - an image become a state of mind.

On Wednesday, the actual anniversary, the Guardian is producing a 12-page broadsheet which will contain about 50 first-person accounts by people around the world whose lives have been affected, some ruined, by September 11 or by the war in Afghanistan and what has followed - the ripple effect.

The editor who commissioned many of these said those in the supplement itself amounted to 20,000 words or so but many more would be available on the website. The voices include a Taliban fighter, an Afghan woman, a New York firefighter, the person in charge of redeveloping Ground Zero, the relative of a person detained in Camp X-ray, a lawyer representing an al-Qaida fugitive...

These will be allowed in the supplement to speak for themselves on unrelieved pages of text facing pages of themed pictures - images of Bin Laden, drawings of the twin towers by children, for example. The art director said that because of the nature of the subject it was important not to try to get the design to do too much. In choosing the pictures, he set himself the task of keeping away from the images that are so familiar - he has allowed himself one small visual reference to the attack on the twin towers, on the first page.

It was a more difficult exercise than he imagined. He looked at several thousand pictures, vast numbers from New York and Afghanistan. Partly due to the advent of digital pictures, he said, the idea that there can be a definitive image that sums up a major event, even one such as this, is starting to disappear.

In fact, an exhibition of more than 1,000 pictures documenting the event and its aftermath in New York opens in the Newsroom, the Guardian's archive and visitor centre (details below) this week, and a selection of those will also be on the website.

A vast effort has gone into trying to mark the anniversary in a useful and thought-provoking way. Let us know what you think.

· The exhibition, Here is New York, opens at the Newsroom, 60 Farringdon Road, London, on September 11 and continues until October 5 (10am to 5pm weekdays, noon to 5pm Saturdays and Sundays, admission free). Readers may contact the office of the readers' editor by telephoning 0845 451 9589 between 11am and 5pm Monday to Friday (all calls are charged at local rate). Mail to Readers' editor, The Guardian, 119 Farringdon Road, London EC1R 3ER. Fax 020-7239 9997. Email: reader@theguardian.com